Additives, typically sanitizing chemicals, suitable for use in automatic toilet bowl cleaner dispensers can be broadly classified as those containing detergents (or surfactants) and those containing oxidants. When automatically dosed into a toilet tank and/or bowl, a detergent reduces the surface tension of the water and concentrates on any oil-water interface to exert an emulsifying action which aids in the removal of stains and soils from the toilet bowl surface. Signal dyes, chelating agents, fragrance oils and other beneficial materials can generally be mixed directly with the detergent.
Cleaners containing an oxidant, on the other hand, provide a strong oxidizing action which bleaches stains, breaks down soils and serves as a disinfectant by killing microorganisms such as bacteria. Materials commonly used to create the oxidizing action are those which produce available chlorine via hypochlorite ions, such as calcium hypochlorite. Signal dyes, surfactants, and other beneficial materials generally cannot be mixed directly with the oxidants.
Although the chemical actions of detergents and oxidants are very different, they both can produce useful toilet cleaning action and, in fact, produce particularly good cleaning when used together, provided that they are sufficiently separated from each other prior to dispensal to the toilet water. Sanitizer dispensers which accomplish this separate dispensing of a detergent and a disinfectant such as an oxidant are disclosed in U.S. Pat. No. 3,504,384 issued to Radley et al. on Apr. 7, 1970 and U.S. Pat. No. 4,216,027, issued to Wages on Aug. 5, 1980.
The current trend in new single cleaner automatic toilet bowl cleaner products is the use of oxidants because small quantities of the oxidants such as calcium hypochlorite can maintain an effective 5 to 10 ppm concentration of available chlorine in the toilet water over a 4-month product life. This product life substantially exceeds the practical limits of about 30 days for detergent type automatic toilet bowl cleaner products.
Such oxidant disinfectant containing products are ordinarily provided in a soluble solid form within a chamber of the dispenser, to be dissolved by a volume of tank water. Each time the toilet is flushed, a predetermined volume of tank water enters the dispenser and a substantially equal volume of solution issues from the dispenser into the tank water. During quiescent periods between flushes, it is desirable to isolate the oxidant solid and oxidant containing solution from the tank water. Dispensers of oxidant disinfectants to toilet water which contain soluble solid oxidant products which operate in this manner are disclosed in the above-mentioned Wages patent, U.S. Pat. Nos. 4,171,546, 4,186,856, and 4,208,747, respectively issued to Dirksing on Oct. 23, 1979, Feb. 5, 1980, and June 24, 1980; U.S. Pat. No. 4,305,162, issued to Cornelisse, Jr. et al. on Dec. 15, 1981, and U.S. Pat. No. 4,307,474, issued to Choy on Dec. 29, 1981.
All of the dispensers disclosed in these patents are completely passive, that is, they have no moving parts, rely upon suction or vacuum transfer for dispensing the solution, and rely entirely upon the formation of air locks in water inlets and solution outlets in order to maintain isolation between the solid and solution in the dispenser, and the tank water, during quiescent periods between flushes of the toilet. The air locks require a balance of hydrostatic pressure between the solution in the dispenser and the surrounding water in the tank. Consequently, when the toilet is flushed and the water level in the tank recedes below the air locks solution in the dispenser, the resulting imbalance in hydrostatic pressure caused the solution to immediately begin to flow into and through the outlet into the tank water.
It is an object of the present invention to provide a simple and inexpensively produced toilet-bowl cleaner dispenser in which a water soluble solid cleaner is stored in a chamber during quiescent periods between flushes isolated from the toilet tank water by at least one positively closing valve and from which a predetermined volume of cleaner containing solution is dispensed without suction each time the toilet is flushed.